The present invention relates to a thermoplastic resin composition with good mechanical strength, impact resistance, thermal deformation resistance, moldability and chemical resistance comprising crystalline polyolefin, polycarbonate and additive components.
Aromatic polycarbonates have excellent impact strength, heat resistance, rigidity and dimension stability, but they are poor in solvent resistance and moldability. To overcome these problems, attempts have been made to provide polycarbonate compositions with polyolefins. However, since polyolefins and polycarbonates do not have good compatibility, proposals have been made to add various third components to improve their compatibility.
Japanese Patent Laid-Open No. 57-108151 discloses a polycarbonate resin composition comprising 100 parts by weight of a polycarbonate resin, 0.3-20 parts by weight of polyethylene and 0.3-20 parts by weight of a butyl rubber.
Japanese Patent Laid-Open No. 57-108152 discloses a polycarbonate resin composition comprising 0.3-20 parts by weight of an ethylene-propylene copolymer and/or an ethylene-propylene-diene copolymer as a third component.
Japanese Patent Laid-Open No. 57-111351 discloses a polycarbonate resin composition comprising 0.3-20 parts by weight of an isoprene rubber and/or a methylpentene polymer as a third component.
Any of these polycarbonate resin compositions, however, suffers from drastic decrease in impact strength when polyethylene content exceeds 10 %, resulting in the surface peel of molded products.
Further, there are various proposals in adding third components. For instance, Japanese Patent Laid-Open Nos. 56-76449 and 59-133247 disclose thermoplastic resin compositions comprising polycarbonate, polyolefin and an ABS resin. However, the ABS resin do not have sufficient effects of increasing compatibility, so when polyolefin exceeds 10 %, the thermoplastic resin compositions lose mechanical strength.
Japanese Patent Laid-Open No. 59-196360 discloses a polycarbonate resin composition comprising as a third component a copolymer of at least one olefin and an acrylate, methacrylate, acrylic acid or methacrylic acid monomer, for instance, an ethylene-ethyl acrylate copolymer (EEA resin).
Japanese Patent Laid-Open No. 61-215649 discloses a polycarbonate resin composition comprising as a third component an olefin-vinyl ester copolymer, for instance, an ethylene-vinyl acetate copolymer (EVA resin), etc.
However, these compositions also suffer from decrease in impact strength due to the decrease in compatibility when the amount of polyolefin nears that of polycarbonate.
Japanese Patent Laid-Open No. 61-115945 discloses a composition comprising a styrene-ethylene.multidot.butylene-styrene block copolymer (SEBS resin) as a third component. However, the addition of the SEBS resin fails to provide sufficient rigidity, thermal deformation resistance, impact strength, surface peel resistance, etc., though the compatibility is slightly improved.
Japanese Patent Publication Nos. 51-24540 and 51-41145 and Japanese Patent Laid-Open No. 60-233151 disclose thermoplastic resin compositions comprising polycarbonate and a graft copolymer produced by grafting a styrene monomer and acrylonitrile monomer to an ethylene-propylene-diene copolymer (AES resin). However, since none of these thermoplastic resin compositions contains polyolefin, they are poor in moldability.
In addition, Japanese Patent Laid-Open Nos. 61-159447, 61-120852, 61-225245, 61-235456 and 61-238847 disclose compositions comprising aromatic polycarbonate, polyester and/or modified polyolefin, etc. Further, Japanese Patent Laid-Open No. 49-76948 discloses a thermoplastic resin composition comprising polycarbonate and a styrene-maleic anhydride copolymer. However, since no polyolefin is contained in these compositions, they are poor in solvent resistance.
As described above, although thermoplastic resin compositions based on polycarbonate and polyolefin whose compatibility is improved to have an excellent balance of mechanical strength, moldability and solvent resistance are desired particularly for automobile parts, etc., satisfactory compositions have never been provided.